Fix positional nested parameter array parsing

[TeamDman]

A nested command structure caused me problems, see #69

    #[derive(Facet, Debug, PartialEq)]
    struct GradleCommand {
        #[facet(args::positional)]
        tasks: Vec<String>,

        #[facet(rename = "hide-logs", args::named, default = false)]
        hide_logs: bool,
    }

    #[derive(Facet, Debug, PartialEq)]
    #[repr(u8)]
    enum Command {
        Gradle {
            #[facet(flatten)]
            command: GradleCommand,
        },
    }

    #[derive(Facet, Debug, PartialEq)]
    struct Cli {
        #[facet(args::subcommand)]
        command: Command,
    }

The following would fail to parse if there was exactly one item specified

gradle runData

Error: unexpected token: got scalar, expected sequence start at command::Gradle.tasks
   ╭─[ <cli>:1:8 ]
   │
 1 │ gradle runData
   │        ───┬───
   │           ╰───── unexpected token: got scalar, expected sequence start at command::Gradle.tasks
───╯


error: test failed, to rerun pass `-p figue --test main`

The existing behaviour would succeed if multiple items were passed, however

gradle runData test

happy

Disclaimer: this fix was created by GPT-5.3 Codex.

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Snapshot tests dislike windows lol

[Copilot]

Pull request overview

Fixes a CLI parsing edge case where positional Vec<T> fields inside a flattened subcommand payload would fail when exactly one item was provided (issue #69).

Changes:

• Add coverage for flattened-subcommand positional Vec<String> parsing with single vs multiple tokens.
• Teach the CLI layer to insert an array on first assignment when the target arg schema is multiple (so Vec<T> deserializes correctly even with a single value).
• Propagate multiple metadata through parent-flag (“adoption agency”) lookups and flag parsing helpers.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
crates/figue/tests/integration/sequence.rs	Adds regression tests for flattened subcommand positional Vec<String> (single + multiple tokens).
crates/figue/src/layers/cli.rs	Adds is_multiple tracking and ensures single occurrences of multiple args are stored as arrays.

Comments suppressed due to low confidence (1)

crates/figue/src/layers/cli.rs:983

• insert_value_to now takes is_multiple, but the occupied-entry path still always accumulates into an array even when is_multiple is false. That means repeating a non-multiple arg/flag (e.g. --port 1 --port 2) will silently produce a ConfigValue::Array and later fail deserialization with a confusing "expected scalar"-style error. Consider using is_multiple here to either (a) overwrite the previous value (last-one-wins) or (b) emit a dedicated diagnostic for duplicate non-multiple args, and only accumulate when is_multiple is true.

            indexmap::map::Entry::Occupied(mut entry) => {
                // Accumulate into array for repeated flags
                let existing = entry.get_mut();
                if let ConfigValue::Array(arr) = existing {
                    arr.value.push(value);
                } else {
                    // Convert to array with both values
                    let placeholder = ConfigValue::Null(Sourced {
                        value: (),
                        span: None,
                        provenance: None,
                    });
                    let old = core::mem::replace(existing, placeholder);
                    *existing = ConfigValue::Array(Sourced {
                        value: vec![old, value],
                        span: None,
                        provenance: None,
                    });
                }

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[TeamDman]

Existing behaviour

#[test]
fn test_duplicate_non_multiple_named_last_value_wins() {
    #[derive(Facet, Debug)]
    struct Args {
        #[facet(args::named)]
        port: u16,
    }

    let args: Args = figue::from_slice(&["--port", "1", "--port", "2"]).unwrap();
    assert_eq!(args.port, 2);
}

it is an error when a non-array parameter is specified multiple times, which aligns with my expectations

❯ cargo test -p figue --test main test_duplicate_non_multiple_named_last_value_wins -- --nocapture
    Blocking waiting for file lock on build directory
   Compiling figue v1.0.0 (G:\Programming\Repos\figue\crates\figue)
    Finished `test` profile [unoptimized + debuginfo] target(s) in 9.42s
     Running tests\main.rs (target\debug\deps\main-8104c8a25b6a3ae2.exe)

running 1 test
Error: unexpected token: got sequence start, expected scalar value at port      
   ╭─[ <cli>:1:8 ]

running 1 test
Error: unexpected token: got sequence start, expected scalar value at port
   ╭─[ <cli>:1:8 ]
   │
 1 │ --port 1 --port 2
   │        ┬
   │        ╰── unexpected token: got sequence start, expected scalar value at port
───╯

error: test failed, to rerun pass `-p figue --test main`

updating my changes to ensure this remains the case

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

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[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated no new comments.

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